Draft gear



Dec. 8, 1931. w. H. coT'roN DRAFT GEAR Filed Sept. 18, 1925 3 Sheets-Sheet l @99S N9 @my m MN l 1 l l l 1 f l {ay/sf Dec. 8, 1931. w. H. co'rToN DRAFT GEAR Filed Sept. 181925 www 3 Sheets-Sheet 2 [u ynzf: Z/azefff (Mm l C fw q m ww NNN@ Defs, 1931. w, ||l CQTTON 1,835,282

DRAFT GEAR Filed Sept. 18, 1925 3 Sheets-Sheet 3 Ihm.

Patented Dec. 8, 1931 Unirse sTATEs PATENT OFFICE WALTER H..COTT`N, OF CHICAGO, ILLINOIS, ASSIGNOR TO UNION' DRAFT GEAR COM- '1 1 PANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F DELAWARE DRAFT GEAR' Application mea september This invention relates to shock absorbing devices, and more particularly to draft gears for railway cars.

One of the objects of the invention is the provision of new and improved draft gear of such construction that it occupies a minimum amount of space.

Another object of the invention is the provision of a new and improved means for producing lateral pressure on the friction elements during the compression of the gear.

A further object of the invention is the provision of new and improved means and arrangement of parts for promptly returning the elements of the gear to normal position after compression.

A still further object of the invention is the provision of a new and improved gear that is simple in construction, efficient in operation, that is promptly returned to normal position after compression, that is easily assembled, occupies a minimum amount of space, and one that is not likely to become broken or get out of order.

A still further object of the invention is the provision of new and improved means Y for increasing the frictional resistance of the friction elements during the compression of the gear without increasing the size of the gear, or the number of plates, or altering the size or length of the springs that are employed in the conventional gear of this type. Other and further objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a horizontal section of the 'preferred form of draft gear, showing the same in position beneath a railway car, with parts broken away; i v

Fig. 2 is a vertical section on line 2 2 of Fig. 1;

Fig. 3 is a plan view of the wedge element;

Fig. 4 is a perspective view of one of the pressure or wedge plates;

Fig. 5 is a plan view of one of the base plates or spring seats;

Fig. 6 is a detail view showing the friction shoe assembly, with parts in section;

1s, 1925. Serial No. 57,175.

Fig. 7 is a perspective view of one of the wedge or friction shoes;

FigzAS is a perspective view of one of the friction plates;

Fig. 9 is a view similar to Fig. 1,but showing a modified form of the device; Y

Fig. 1() is a section on line 10-10 of Fig. 9;

F ig. 11 is a section on line 11,-11 of Fig. 9;

Fig. 12 is a section onV line 12-12 of Fig. 11; and

Fig. 13 is a perspective view of one of the wedge blocks. i

On the drawings the reference character 1() designates the center sills of a railway car,

each of which is provided with a draft lug 11 and a buffer lug 12. y The improved draft gear is mounted in the usual manner between the lugs 11 and 12 and embraced by the draft yoke 13 which is rigidly secured at its forward end to the draft bar 14.

The draft gear comprises a pair; of follower blocks 15 and 16 between which is interposed two groups of intercalated friction plates, eac-h group` comprising two sets of plates 17 and 18 which in the construction disclosed overlap atv their inner ends. Each plate is reduced as at 20 to form the shoulders 200 for engaging the retracting bars as will presently appear. V

In the present construction of draft gears of the friction Yplatetype it is common practice to provide aseparate sleeve or chambered follower member for embracing each end of the groups of plates. In order to eliminate one of these sleeves or chambered follower members and at the same time shorten the gear without sacrificingr any `of the advantages of this type of gear, a single sleeve or casing is employed for embracing the friction plates. As shown, a sleeve or casing 19 extends about the central portion of the two groups of friction members and is adapted to limit the outward lateral movement of the friction plates. The sleeve may, if desired, beprovided with suitablevstrengthening ribs 20 Suitable means are providedV for creating lateral pressure on the friction plates 17 and 18 during the compression of the gear. Preferably the means providedfor this purpose f forces the plates outwardly against the sleeve or casing 19. As shown, rigid pressure plates, such as the Wedge plates 21, see Fig. 4, are employed for this purpose. Preferably each of these plates has a double wedge-shaped face 22 on one side and a plane surface on the other, and these plates have their plane or fiat surfaces in engagement with the groups of friction plates 17 and 18 at each side of the gear. A pair of wedge shoes 23 is provided at each end of the gear.

Each shoe is provided on its back or outer side with an incline surface 24, see Figs. 1 and 6, for engaging the corresponding incline surface 22 of the wedge plate. Each shoe is also provided on opposite sides with inclined shoulders 25 which are adapted to be engaged by wedges or wedge elements 26 to force the shoes 23 outwardly and forwardly during the compression of the gear.

In the embodiment of the invention shown in Fig. 1, a wedge block comprising two wedges 26 is employed. The wedges are preferably rigidly connected together by the connector member or spring seat 30 which holds the same in proper position in spaced relation to each other.

. Means are provided for resisting the forward movement of the shoes 23 while the gear is being compressed inv order that the wedges 26 may force the shoes laterally to create lateral pressure on the friction plates for absorbing the shocks and the like incident to the movements of the car on which the device is installed. As shown. the wedge shoes 26 are tied together by a base plate or spring seat 27 in any suitable manner. A compression spring 28 is adapted to engage the base plate or spring seat 27 thereby resisting the inward movement of said shoes.

The plates 27 are connected to the shoes 23 in such a manner as to permit the shoes to move laterally. In the form shown, the shoes are provided with apertures 29 ext-ending transversely through their base portions. The outer wall of each aperture is inclined outwardly at the back of the shoe as shown at 31 in Fig. 5. The plate 27 is provided with reduced ends or extensions 32 for engaging the apertures 29, each extension being provided with an inclined shoulder or surface 33 for engaging the corresponding inclined sur faces 31 on the shoes.

Suitable means are provided for centrally positioning the sleeve and the wedge plates 21 and for returning the parts to normal position after compression. One form of mechanism for accomplishing this function will now be described.

The wedge plates 21 are provided on each side edge with spaced lugs 34 which are adapted to engage or interlock with lugs 35 extending inwardly from the inner top and bottom walls of the sleeve 19 across the friction plates as clearly shown in Figs. 2 and 10, of the drawings, for positioning the sleeves after compression of the gear. rFhe shoes 23 are each provided with laterally extending hooks or lugs 36 which are adapted to engage the end walls of recesses 37 in the wedge plates 21 for positioning said plates after compression of the gear. The shoes 23 are also provided with oppositely extending lugs 38 which are adapted to engage retracting bars 39 at opposite sides of the gear at each end thereof. The retracting bars are adapted to engage the shoulders 200 of the friction plates for returning the same to normal position after compression. The reduced portions 2O of the plates permit the retracting bars to slide inwardly independently of the shoes as will be evident from an inspection of Fig. 2 of the drawings.

Resilient means, such as the coil spring 41, is employed for resisting the compression of the gear and for releasing the wedge members 26. As shown, the spring 41 is mounted within the spring 28 and extending through openings 42 in the base plates 27 at each end of the gear engage apertured positioning lugs 43 on the connector member or spring seat 30.

In the operation of the device, assuming force is being applied to compress the gear in Fig. 1, the follower blocks 1a and 16 will ei'lgage the wedges 26, which in turn will tend to cause the shoes 23 to move forwardly along the inclined surfaces 22 of the wedge plates 21 against the tension of the spring. The resistance of the spring will cause the shoes to move laterally to compress the plate wedges and friction plates. The wedge plates 21 being engaged at each end by the shoes and thus subjected to equal opposing forces will not move in either direction, consequently the frictional resistance to the inward movement of the wedges is the same at each end of the gear. The forcing of the shoes 23 against the inclined surfaces 22 of the wedge plates 21 by the wedges 26 results in a double wedging action exerting tremendous lateral pressure on the friction plates so that when the follower plates 15 and 16 engage the friction plates the lateral pressure thereon and the friction developed thereby will be suficient to absorb the shocks under any and all conditions.

The above arrangement insuresa prompt release of the gear and an immediate return of the parts to normal position. After compression, the springs 28 and 41 may simultaneously release both the wedges and the shoes since both are provided with inclined or wedging surfaces whereby an outward movement of either or both will release the pressure on the friction plates. The cooperating surfaces 31 and 33 on the base plates 27 and the shoes 23 will prevent the shoes from moving laterally outwardly, and to that extent will assist in releasing the gear. As the shoes move rearward the hooks 36 engage 55 face, and a pair of inclined front surfaces,

the wedge plates 21 and position the same, which in turn will position the sleeve 19. The lugs 38 on the shoes will engage the retracting bars, which in turn will engage the shoulders 200 on the friction plates and re turn said plates to normal position.

The form of the device shown in Figs. 9 to 13 inclusive differs from that just described in that the wedge blocks or elements 45, 45 at each end of the gear are separate and independent of each other. The intercalated friction plates 46 and 47 are much shorter than in Figs. l and 2, the shouldersv 46 being also located nearer the ends of the plates than in the previously described device. In this form of the device the springs 48 and 49 both engage the plate or spring seat 5l that connects the shoes 23.

In the operation of this device, the springs 48 and 49 will resist the inward movement of the shoes 23 during compression of the gear whereby the wedges 45 will force the shoes laterally to compress the friction plates, which on further compression of the gear will engage the followers and yieldingly resist further compression of the gear in the usual manner. On release of compression, the springs 48 and 49 will move the shoes 23 outwardly along the inclines 22 on the plates 2l thereby relieving the lateral pressure on said plates and permitting the parts to be returned to normal position. Furthermore, the bluntness of the wedges 45 and the cooperation of the inclined surfaces 3l and 33 will cause the wedges 45 to be forced outwardly when the gear is released thus relieving the lateral pressure on the friction plates and permitting the springs to return the gear to normal expanded position.

In this form of the device the parts of the gear proper, except the wedges, may be assembled before being inserted between the center sills and held in assembled relation by the engagement of the hooks or lugs 36 in the outer end walls of the recesses 3?. The form of the device shown in Figs. l to 8 may be held assembled in like manner except for the wedges and the central spring. In the latter form, the bosses or lugs 43 are provided with alined apertures for receiving the ends of a telescopic rod which may be employed for secuing the gear assembled during shipment in the usual manner, if desired.

It is thought from the foregoing taken in connection with the .accompanying drawings that the construction and operation of my device will be apparent to those skilled in the art, and that various changes in size, shape, proportion and details of construction may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. A shoe for draft gears for railway cars comprising a member having a flat rear sursaid shoe being provided with a transverse opening'inthebody portion adjacent one end thereof, said opening having an inclined wall adjacentone lend of said-body portion, and a lug at each side and one on the back of said body portion.- i Y A friction shoe for a draft gear comprising va member provided with side walls and a baclrwall, saidback wall being provided. with: a: surface yinclined to the longitudinal aXisof said'shoe for engaging a pressure plat'eysaidback lwall being provided with a projection: adapted to engage an opening in said .pressure plate, said side walls each being provided witha wedging surface which isV adapted to be engaged by a wedge block, said last-named surfaces being in a plane at an angle to said first-named surface, and lugs on said side walls adapted to engage retracting bars.

3. In a draft lgear, a pair of follower mem bers, two sets of intercalated friction plates between said follower members, one set of said plates being operated by one of said followers and the other set by the other follower during the compression of the gear, means including a plurality of friction shoes and'cooperating wedge members for engaging said followers and plates at each end of said gear for creating lateral pressure on said plates during the compression` of said gear, said wedge members each comprising a pair of wedge elements, a connector plate connecting said elements, a single sleeve member embracing said friction plates for limiting their outward movement, means for resisting the lateral pressure on said plates, means for revsiliently resisting the inward movement'of said plates, and means including a spring engaging said connector plates for restoring the parts to normal position after said release.

' 4. In a draft gear, a pair of follower members, two sets of intercalated friction plates between said follower members, one set of said plates being operated by one of said followers and the other set by the other follower during the compression of the gear. means including a plurality of friction shoes and cooperating wedge members for engaging said followers and plates for creating lat; eral pressure on said plates during the compression of said gear, means for resisting the lateral pressure on said plates, means for resiliently resisting the inward movement of said plates, a spring seat, cooperating wedging connection between said seat and the outer ends of said shoes for wedging said shoes in a direction away from said plates during the release movement of said gear.

5. In a friction draft gear, the combination of an open-ended casing, a follower at each end of said casing, two sets of intercalated friction plates within said casing, one set of said plates being adapted to be enles CFI

gaged by one of said followers and the other set by the other follower, for moving said plates inwardly during the compression of the gear, a pair of pressure plates in engagement with said sets of friction plates, each of said pressure plates having a wedgeshaped surface at each end thereof, means including a pair of friction shoes at each end of said gear, and a Wedge member in engagement with said followers and shoes for creating lateral pressure on said plates during the compression of the gear, and an interlocking connection between said pressure plates and the inner ends of said shoes.

In testimony whereof I affix my signature.

WALTER H. COTTON. 

